This study is predicated on the assumption that there may be optimal levels of cerebral perfusion pressure (CPP) and its components, intracranial pressure (ICP) and systemic arterial blood pressure (ABP), that help prevent or reduce secondary brain injury in critically ill patients. Since CPP can be influenced by nursing care such as positioning, suctioning and the like, refining the ability for nurses to manage CPP on a minute-to-minute basis is currently being tested for the ability to demonstrate measurable improvement in short and long-term outcome for late adolescents and adults. In this competing continuation, we propose to extend the observation to children, for whom no adequate threshold has yet been determined, to examine complexity of physiologic waveforms to better understand the variations that may underlie clinical outcome differences or better predict outcome variation, and to conduct a cost-analysis of this improvement in technology. The specific aims of the competing continuation are to: 1) Determine if CPP threshold can be defined for children less than 16 years of age, based on 3, 6 and 12 month outcomes; 2) Characterize ICP and ABP complexity and HRV for both adults and children in relation to predicting outcome at discharge and 6 and 12 months (for children); 3) Estimate hospitalization cost across the life span for children, adolescents and adults monitored for CPP; 4) Estimate the value, in quality adjusted life years (QALY) for varying outcomes of care across the life span for children, adolescents and adults monitored for CPP. Computer interfaces that provide visual information about CPP will be allocated to beds in each of the pediatric intensive care units used for children ages 1-16 years with traumatic injury, in whom ICP and blood pressure monitoring has been instituted as part of medical management. Data regarding CPP and 3, 6 and 12-month functional outcome will be evaluated to determine if a threshold for CPP can be determined for differing grades of outcome (from death to very good physical and social function). Continuous ICP, ABP and electrocardiographic data from these children and from the adults in the parent study will be analyzed using a variety of non-linear approaches to determine waveform factors that are predictive of outcome. Hospital data regarding costs and charges during acute care hospitalization will be examined in both children and adults to determine if the use of the computer interface is associated with greater or lesser acute care costs. Finally, a survey of survivors of acute brain injury and of community peers will be conducted to estimate the value (in quality adjusted life years) placed on differing outcome states after both traumatic brain injury and aneurysmal subarachnoid hemorrhage.